[unreadable] [unreadable] The proposed research will help elucidate the molecular mechanisms and regulatory elements governing endocytosis via caveolae. Specifically, an in vitro caveolae budding assay will be used to determine the roles of actin and caveolin-1 in stabilizing caveolae at the cell surface. Furthermore, the budding assay and column chromatography will be used to identify the cytosolic factors required for caveolae budding. The roles of PKC (alpha) and the serum deprivation response protein in regulating caveolae budding will be investigated using RNAi knockdown and the in vitro assay. Furthermore, the influence of ligand binding on receptor internalization by caveolae will be investigated. All factors identified using the in vitro assay will be tested for their relevance in whole cells. Many disease-causing agents including bacteria (e.g. Chlamidia trechomatis) viruses (e.g. the Ebola and Marburg filoviruses), and bacterial toxins (e.g. cholera toxin) are internalized through caveolae, thus bypassing pathways that lead to degradation in lysosomes. Therefore, a deeper understanding of the regulation of caveolae budding could lead to clinical applications. [unreadable] [unreadable] [unreadable]